drivers/iommu/ipmmu-vmsa.c

// SPDX-License-Identifier: GPL-2.0
/*
 * IOMMU API for Renesas VMSA-compatible IPMMU
 * Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *
 * Copyright (C) 2014-2020 Renesas Electronics Corporation
 */

#include <linux/bitmap.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/io-pgtable.h>
#include <linux/iommu.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/sys_soc.h>

#if defined(CONFIG_ARM) && !defined(CONFIG_IOMMU_DMA)
#include <asm/dma-iommu.h>
#else
#define arm_iommu_create_mapping(...)	NULL
#define arm_iommu_attach_device(...)	-ENODEV
#define arm_iommu_release_mapping(...)	do {} while (0)
#endif

#define IPMMU_CTX_MAX		16U
#define IPMMU_CTX_INVALID	-1

#define IPMMU_UTLB_MAX		64U

struct ipmmu_features {
	bool use_ns_alias_offset;
	bool has_cache_leaf_nodes;
	unsigned int number_of_contexts;
	unsigned int num_utlbs;
	bool setup_imbuscr;
	bool twobit_imttbcr_sl0;
	bool reserved_context;
	bool cache_snoop;
	unsigned int ctx_offset_base;
	unsigned int ctx_offset_stride;
	unsigned int utlb_offset_base;
};

struct ipmmu_vmsa_device {
	struct device *dev;
	void __iomem *base;
	struct iommu_device iommu;
	struct ipmmu_vmsa_device *root;
	const struct ipmmu_features *features;
	unsigned int num_ctx;
	spinlock_t lock;			/* Protects ctx and domains[] */
	DECLARE_BITMAP(ctx, IPMMU_CTX_MAX);
	struct ipmmu_vmsa_domain *domains[IPMMU_CTX_MAX];
	s8 utlb_ctx[IPMMU_UTLB_MAX];

	struct dma_iommu_mapping *mapping;
};

struct ipmmu_vmsa_domain {
	struct ipmmu_vmsa_device *mmu;
	struct iommu_domain io_domain;

	struct io_pgtable_cfg cfg;
	struct io_pgtable_ops *iop;

	unsigned int context_id;
	struct mutex mutex;			/* Protects mappings */
};

static struct ipmmu_vmsa_domain *to_vmsa_domain(struct iommu_domain *dom)
{
	return container_of(dom, struct ipmmu_vmsa_domain, io_domain);
}

static struct ipmmu_vmsa_device *to_ipmmu(struct device *dev)
{
	return dev_iommu_priv_get(dev);
}

#define TLB_LOOP_TIMEOUT		100	/* 100us */

/* -----------------------------------------------------------------------------
 * Registers Definition
 */

#define IM_NS_ALIAS_OFFSET		0x800

/* MMU "context" registers */
#define IMCTR				0x0000		/* R-Car Gen2/3 */
#define IMCTR_INTEN			(1 << 2)	/* R-Car Gen2/3 */
#define IMCTR_FLUSH			(1 << 1)	/* R-Car Gen2/3 */
#define IMCTR_MMUEN			(1 << 0)	/* R-Car Gen2/3 */

#define IMTTBCR				0x0008		/* R-Car Gen2/3 */
#define IMTTBCR_EAE			(1 << 31)	/* R-Car Gen2/3 */
#define IMTTBCR_SH0_INNER_SHAREABLE	(3 << 12)	/* R-Car Gen2 only */
#define IMTTBCR_ORGN0_WB_WA		(1 << 10)	/* R-Car Gen2 only */
#define IMTTBCR_IRGN0_WB_WA		(1 << 8)	/* R-Car Gen2 only */
#define IMTTBCR_SL0_TWOBIT_LVL_1	(2 << 6)	/* R-Car Gen3 only */
#define IMTTBCR_SL0_LVL_1		(1 << 4)	/* R-Car Gen2 only */

#define IMBUSCR				0x000c		/* R-Car Gen2 only */
#define IMBUSCR_DVM			(1 << 2)	/* R-Car Gen2 only */
#define IMBUSCR_BUSSEL_MASK		(3 << 0)	/* R-Car Gen2 only */

#define IMTTLBR0			0x0010		/* R-Car Gen2/3 */
#define IMTTUBR0			0x0014		/* R-Car Gen2/3 */

#define IMSTR				0x0020		/* R-Car Gen2/3 */
#define IMSTR_MHIT			(1 << 4)	/* R-Car Gen2/3 */
#define IMSTR_ABORT			(1 << 2)	/* R-Car Gen2/3 */
#define IMSTR_PF			(1 << 1)	/* R-Car Gen2/3 */
#define IMSTR_TF			(1 << 0)	/* R-Car Gen2/3 */

#define IMMAIR0				0x0028		/* R-Car Gen2/3 */

#define IMELAR				0x0030		/* R-Car Gen2/3, IMEAR on R-Car Gen2 */
#define IMEUAR				0x0034		/* R-Car Gen3 only */

/* uTLB registers */
#define IMUCTR(n)			((n) < 32 ? IMUCTR0(n) : IMUCTR32(n))
#define IMUCTR0(n)			(0x0300 + ((n) * 16))		/* R-Car Gen2/3 */
#define IMUCTR32(n)			(0x0600 + (((n) - 32) * 16))	/* R-Car Gen3 only */
#define IMUCTR_TTSEL_MMU(n)		((n) << 4)	/* R-Car Gen2/3 */
#define IMUCTR_FLUSH			(1 << 1)	/* R-Car Gen2/3 */
#define IMUCTR_MMUEN			(1 << 0)	/* R-Car Gen2/3 */

#define IMUASID(n)			((n) < 32 ? IMUASID0(n) : IMUASID32(n))
#define IMUASID0(n)			(0x0308 + ((n) * 16))		/* R-Car Gen2/3 */
#define IMUASID32(n)			(0x0608 + (((n) - 32) * 16))	/* R-Car Gen3 only */

/* -----------------------------------------------------------------------------
 * Root device handling
 */

static struct platform_driver ipmmu_driver;

static bool ipmmu_is_root(struct ipmmu_vmsa_device *mmu)
{
	return mmu->root == mmu;
}

static int __ipmmu_check_device(struct device *dev, void *data)
{
	struct ipmmu_vmsa_device *mmu = dev_get_drvdata(dev);
	struct ipmmu_vmsa_device **rootp = data;

	if (ipmmu_is_root(mmu))
		*rootp = mmu;

	return 0;
}

static struct ipmmu_vmsa_device *ipmmu_find_root(void)
{
	struct ipmmu_vmsa_device *root = NULL;

	return driver_for_each_device(&ipmmu_driver.driver, NULL, &root,
				      __ipmmu_check_device) == 0 ? root : NULL;
}

/* -----------------------------------------------------------------------------
 * Read/Write Access
 */

static u32 ipmmu_read(struct ipmmu_vmsa_device *mmu, unsigned int offset)
{
	return ioread32(mmu->base + offset);
}

static void ipmmu_write(struct ipmmu_vmsa_device *mmu, unsigned int offset,
			u32 data)
{
	iowrite32(data, mmu->base + offset);
}

static unsigned int ipmmu_ctx_reg(struct ipmmu_vmsa_device *mmu,
				  unsigned int context_id, unsigned int reg)
{
	unsigned int base = mmu->features->ctx_offset_base;

	if (context_id > 7)
		base += 0x800 - 8 * 0x40;

	return base + context_id * mmu->features->ctx_offset_stride + reg;
}

static u32 ipmmu_ctx_read(struct ipmmu_vmsa_device *mmu,
			  unsigned int context_id, unsigned int reg)
{
	return ipmmu_read(mmu, ipmmu_ctx_reg(mmu, context_id, reg));
}

static void ipmmu_ctx_write(struct ipmmu_vmsa_device *mmu,
			    unsigned int context_id, unsigned int reg, u32 data)
{
	ipmmu_write(mmu, ipmmu_ctx_reg(mmu, context_id, reg), data);
}

static u32 ipmmu_ctx_read_root(struct ipmmu_vmsa_domain *domain,
			       unsigned int reg)
{
	return ipmmu_ctx_read(domain->mmu->root, domain->context_id, reg);
}

static void ipmmu_ctx_write_root(struct ipmmu_vmsa_domain *domain,
				 unsigned int reg, u32 data)
{
	ipmmu_ctx_write(domain->mmu->root, domain->context_id, reg, data);
}

static void ipmmu_ctx_write_all(struct ipmmu_vmsa_domain *domain,
				unsigned int reg, u32 data)
{
	if (domain->mmu != domain->mmu->root)
		ipmmu_ctx_write(domain->mmu, domain->context_id, reg, data);

	ipmmu_ctx_write(domain->mmu->root, domain->context_id, reg, data);
}

static u32 ipmmu_utlb_reg(struct ipmmu_vmsa_device *mmu, unsigned int reg)
{
	return mmu->features->utlb_offset_base + reg;
}

static void ipmmu_imuasid_write(struct ipmmu_vmsa_device *mmu,
				unsigned int utlb, u32 data)
{
	ipmmu_write(mmu, ipmmu_utlb_reg(mmu, IMUASID(utlb)), data);
}

static void ipmmu_imuctr_write(struct ipmmu_vmsa_device *mmu,
			       unsigned int utlb, u32 data)
{
	ipmmu_write(mmu, ipmmu_utlb_reg(mmu, IMUCTR(utlb)), data);
}

/* -----------------------------------------------------------------------------
 * TLB and microTLB Management
 */

/* Wait for any pending TLB invalidations to complete */
static void ipmmu_tlb_sync(struct ipmmu_vmsa_domain *domain)
{
	u32 val;

	if (read_poll_timeout_atomic(ipmmu_ctx_read_root, val,
				     !(val & IMCTR_FLUSH), 1, TLB_LOOP_TIMEOUT,
				     false, domain, IMCTR))
		dev_err_ratelimited(domain->mmu->dev,
			"TLB sync timed out -- MMU may be deadlocked\n");
}

static void ipmmu_tlb_invalidate(struct ipmmu_vmsa_domain *domain)
{
	u32 reg;

	reg = ipmmu_ctx_read_root(domain, IMCTR);
	reg |= IMCTR_FLUSH;
	ipmmu_ctx_write_all(domain, IMCTR, reg);

	ipmmu_tlb_sync(domain);
}

/*
 * Enable MMU translation for the microTLB.
 */
static void ipmmu_utlb_enable(struct ipmmu_vmsa_domain *domain,
			      unsigned int utlb)
{
	struct ipmmu_vmsa_device *mmu = domain->mmu;

	/*
	 * TODO: Reference-count the microTLB as several bus masters can be
	 * connected to the same microTLB.
	 */

	/* TODO: What should we set the ASID to ? */
	ipmmu_imuasid_write(mmu, utlb, 0);
	/* TODO: Do we need to flush the microTLB ? */
	ipmmu_imuctr_write(mmu, utlb, IMUCTR_TTSEL_MMU(domain->context_id) |
				      IMUCTR_FLUSH | IMUCTR_MMUEN);
	mmu->utlb_ctx[utlb] = domain->context_id;
}

/*
 * Disable MMU translation for the microTLB.
 */
static void ipmmu_utlb_disable(struct ipmmu_vmsa_domain *domain,
			       unsigned int utlb)
{
	struct ipmmu_vmsa_device *mmu = domain->mmu;

	ipmmu_imuctr_write(mmu, utlb, 0);
	mmu->utlb_ctx[utlb] = IPMMU_CTX_INVALID;
}

static void ipmmu_tlb_flush_all(void *cookie)
{
	struct ipmmu_vmsa_domain *domain = cookie;

	ipmmu_tlb_invalidate(domain);
}

static void ipmmu_tlb_flush(unsigned long iova, size_t size,
				size_t granule, void *cookie)
{
	ipmmu_tlb_flush_all(cookie);
}

static const struct iommu_flush_ops ipmmu_flush_ops = {
	.tlb_flush_all = ipmmu_tlb_flush_all,
	.tlb_flush_walk = ipmmu_tlb_flush,
};

/* -----------------------------------------------------------------------------
 * Domain/Context Management
 */

static int ipmmu_domain_allocate_context(struct ipmmu_vmsa_device *mmu,
					 struct ipmmu_vmsa_domain *domain)
{
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&mmu->lock, flags);

	ret = find_first_zero_bit(mmu->ctx, mmu->num_ctx);
	if (ret != mmu->num_ctx) {
		mmu->domains[ret] = domain;
		set_bit(ret, mmu->ctx);
	} else
		ret = -EBUSY;

	spin_unlock_irqrestore(&mmu->lock, flags);

	return ret;
}

static void ipmmu_domain_free_context(struct ipmmu_vmsa_device *mmu,
				      unsigned int context_id)
{
	unsigned long flags;

	spin_lock_irqsave(&mmu->lock, flags);

	clear_bit(context_id, mmu->ctx);
	mmu->domains[context_id] = NULL;

	spin_unlock_irqrestore(&mmu->lock, flags);
}

static void ipmmu_domain_setup_context(struct ipmmu_vmsa_domain *domain)
{
	u64 ttbr;
	u32 tmp;

	/* TTBR0 */
	ttbr = domain->cfg.arm_lpae_s1_cfg.ttbr;
	ipmmu_ctx_write_root(domain, IMTTLBR0, ttbr);
	ipmmu_ctx_write_root(domain, IMTTUBR0, ttbr >> 32);

	/*
	 * TTBCR
	 * We use long descriptors and allocate the whole 32-bit VA space to
	 * TTBR0.
	 */
	if (domain->mmu->features->twobit_imttbcr_sl0)
		tmp = IMTTBCR_SL0_TWOBIT_LVL_1;
	else
		tmp = IMTTBCR_SL0_LVL_1;

	if (domain->mmu->features->cache_snoop)
		tmp |= IMTTBCR_SH0_INNER_SHAREABLE | IMTTBCR_ORGN0_WB_WA |
		       IMTTBCR_IRGN0_WB_WA;

	ipmmu_ctx_write_root(domain, IMTTBCR, IMTTBCR_EAE | tmp);

	/* MAIR0 */
	ipmmu_ctx_write_root(domain, IMMAIR0,
			     domain->cfg.arm_lpae_s1_cfg.mair);

	/* IMBUSCR */
	if (domain->mmu->features->setup_imbuscr)
		ipmmu_ctx_write_root(domain, IMBUSCR,
				     ipmmu_ctx_read_root(domain, IMBUSCR) &
				     ~(IMBUSCR_DVM | IMBUSCR_BUSSEL_MASK));

	/*
	 * IMSTR
	 * Clear all interrupt flags.
	 */
	ipmmu_ctx_write_root(domain, IMSTR, ipmmu_ctx_read_root(domain, IMSTR));

	/*
	 * IMCTR
	 * Enable the MMU and interrupt generation. The long-descriptor
	 * translation table format doesn't use TEX remapping. Don't enable AF
	 * software management as we have no use for it. Flush the TLB as
	 * required when modifying the context registers.
	 */
	ipmmu_ctx_write_all(domain, IMCTR,
			    IMCTR_INTEN | IMCTR_FLUSH | IMCTR_MMUEN);
}

static int ipmmu_domain_init_context(struct ipmmu_vmsa_domain *domain)
{
	int ret;

	/*
	 * Allocate the page table operations.
	 *
	 * VMSA states in section B3.6.3 "Control of Secure or Non-secure memory
	 * access, Long-descriptor format" that the NStable bit being set in a
	 * table descriptor will result in the NStable and NS bits of all child
	 * entries being ignored and considered as being set. The IPMMU seems
	 * not to comply with this, as it generates a secure access page fault
	 * if any of the NStable and NS bits isn't set when running in
	 * non-secure mode.
	 */
	domain->cfg.quirks = IO_PGTABLE_QUIRK_ARM_NS;
	domain->cfg.pgsize_bitmap = SZ_1G | SZ_2M | SZ_4K;
	domain->cfg.ias = 32;
	domain->cfg.oas = 40;
	domain->cfg.tlb = &ipmmu_flush_ops;
	domain->io_domain.geometry.aperture_end = DMA_BIT_MASK(32);
	domain->io_domain.geometry.force_aperture = true;
	/*
	 * TODO: Add support for coherent walk through CCI with DVM and remove
	 * cache handling. For now, delegate it to the io-pgtable code.
	 */
	domain->cfg.coherent_walk = false;
	domain->cfg.iommu_dev = domain->mmu->root->dev;

	/*
	 * Find an unused context.
	 */
	ret = ipmmu_domain_allocate_context(domain->mmu->root, domain);
	if (ret < 0)
		return ret;

	domain->context_id = ret;

	domain->iop = alloc_io_pgtable_ops(ARM_32_LPAE_S1, &domain->cfg,
					   domain);
	if (!domain->iop) {
		ipmmu_domain_free_context(domain->mmu->root,
					  domain->context_id);
		return -EINVAL;
	}

	ipmmu_domain_setup_context(domain);
	return 0;
}

static void ipmmu_domain_destroy_context(struct ipmmu_vmsa_domain *domain)
{
	if (!domain->mmu)
		return;

	/*
	 * Disable the context. Flush the TLB as required when modifying the
	 * context registers.
	 *
	 * TODO: Is TLB flush really needed ?
	 */
	ipmmu_ctx_write_all(domain, IMCTR, IMCTR_FLUSH);
	ipmmu_tlb_sync(domain);
	ipmmu_domain_free_context(domain->mmu->root, domain->context_id);
}

/* -----------------------------------------------------------------------------
 * Fault Handling
 */

static irqreturn_t ipmmu_domain_irq(struct ipmmu_vmsa_domain *domain)
{
	const u32 err_mask = IMSTR_MHIT | IMSTR_ABORT | IMSTR_PF | IMSTR_TF;
	struct ipmmu_vmsa_device *mmu = domain->mmu;
	unsigned long iova;
	u32 status;

	status = ipmmu_ctx_read_root(domain, IMSTR);
	if (!(status & err_mask))
		return IRQ_NONE;

	iova = ipmmu_ctx_read_root(domain, IMELAR);
	if (IS_ENABLED(CONFIG_64BIT))
		iova |= (u64)ipmmu_ctx_read_root(domain, IMEUAR) << 32;

	/*
	 * Clear the error status flags. Unlike traditional interrupt flag
	 * registers that must be cleared by writing 1, this status register
	 * seems to require 0. The error address register must be read before,
	 * otherwise its value will be 0.
	 */
	ipmmu_ctx_write_root(domain, IMSTR, 0);

	/* Log fatal errors. */
	if (status & IMSTR_MHIT)
		dev_err_ratelimited(mmu->dev, "Multiple TLB hits @0x%lx\n",
				    iova);
	if (status & IMSTR_ABORT)
		dev_err_ratelimited(mmu->dev, "Page Table Walk Abort @0x%lx\n",
				    iova);

	if (!(status & (IMSTR_PF | IMSTR_TF)))
		return IRQ_NONE;

	/*
	 * Try to handle page faults and translation faults.
	 *
	 * TODO: We need to look up the faulty device based on the I/O VA. Use
	 * the IOMMU device for now.
	 */
	if (!report_iommu_fault(&domain->io_domain, mmu->dev, iova, 0))
		return IRQ_HANDLED;

	dev_err_ratelimited(mmu->dev,
			    "Unhandled fault: status 0x%08x iova 0x%lx\n",
			    status, iova);

	return IRQ_HANDLED;
}

static irqreturn_t ipmmu_irq(int irq, void *dev)
{
	struct ipmmu_vmsa_device *mmu = dev;
	irqreturn_t status = IRQ_NONE;
	unsigned int i;
	unsigned long flags;

	spin_lock_irqsave(&mmu->lock, flags);

	/*
	 * Check interrupts for all active contexts.
	 */
	for (i = 0; i < mmu->num_ctx; i++) {
		if (!mmu->domains[i])
			continue;
		if (ipmmu_domain_irq(mmu->domains[i]) == IRQ_HANDLED)
			status = IRQ_HANDLED;
	}

	spin_unlock_irqrestore(&mmu->lock, flags);

	return status;
}

/* -----------------------------------------------------------------------------
 * IOMMU Operations
 */

static struct iommu_domain *ipmmu_domain_alloc_paging(struct device *dev)
{
	struct ipmmu_vmsa_domain *domain;

	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
	if (!domain)
		return NULL;

	mutex_init(&domain->mutex);

	return &domain->io_domain;
}

static void ipmmu_domain_free(struct iommu_domain *io_domain)
{
	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);

	/*
	 * Free the domain resources. We assume that all devices have already
	 * been detached.
	 */
	ipmmu_domain_destroy_context(domain);
	free_io_pgtable_ops(domain->iop);
	kfree(domain);
}

static int ipmmu_attach_device(struct iommu_domain *io_domain,
			       struct device *dev)
{
	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);
	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);
	unsigned int i;
	int ret = 0;

	if (!mmu) {
		dev_err(dev, "Cannot attach to IPMMU\n");
		return -ENXIO;
	}

	mutex_lock(&domain->mutex);

	if (!domain->mmu) {
		/* The domain hasn't been used yet, initialize it. */
		domain->mmu = mmu;
		ret = ipmmu_domain_init_context(domain);
		if (ret < 0) {
			dev_err(dev, "Unable to initialize IPMMU context\n");
			domain->mmu = NULL;
		} else {
			dev_info(dev, "Using IPMMU context %u\n",
				 domain->context_id);
		}
	} else if (domain->mmu != mmu) {
		/*
		 * Something is wrong, we can't attach two devices using
		 * different IOMMUs to the same domain.
		 */
		ret = -EINVAL;
	} else
		dev_info(dev, "Reusing IPMMU context %u\n", domain->context_id);

	mutex_unlock(&domain->mutex);

	if (ret < 0)
		return ret;

	for (i = 0; i < fwspec->num_ids; ++i)
		ipmmu_utlb_enable(domain, fwspec->ids[i]);

	return 0;
}

static int ipmmu_iommu_identity_attach(struct iommu_domain *identity_domain,
				       struct device *dev)
{
	struct iommu_domain *io_domain = iommu_get_domain_for_dev(dev);
	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
	struct ipmmu_vmsa_domain *domain;
	unsigned int i;

	if (io_domain == identity_domain || !io_domain)
		return 0;

	domain = to_vmsa_domain(io_domain);
	for (i = 0; i < fwspec->num_ids; ++i)
		ipmmu_utlb_disable(domain, fwspec->ids[i]);

	/*
	 * TODO: Optimize by disabling the context when no device is attached.
	 */
	return 0;
}

static struct iommu_domain_ops ipmmu_iommu_identity_ops = {
	.attach_dev = ipmmu_iommu_identity_attach,
};

static struct iommu_domain ipmmu_iommu_identity_domain = {
	.type = IOMMU_DOMAIN_IDENTITY,
	.ops = &ipmmu_iommu_identity_ops,
};

static int ipmmu_map(struct iommu_domain *io_domain, unsigned long iova,
		     phys_addr_t paddr, size_t pgsize, size_t pgcount,
		     int prot, gfp_t gfp, size_t *mapped)
{
	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);

	return domain->iop->map_pages(domain->iop, iova, paddr, pgsize, pgcount,
				      prot, gfp, mapped);
}

static size_t ipmmu_unmap(struct iommu_domain *io_domain, unsigned long iova,
			  size_t pgsize, size_t pgcount,
			  struct iommu_iotlb_gather *gather)
{
	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);

	return domain->iop->unmap_pages(domain->iop, iova, pgsize, pgcount, gather);
}

static void ipmmu_flush_iotlb_all(struct iommu_domain *io_domain)
{
	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);

	if (domain->mmu)
		ipmmu_tlb_flush_all(domain);
}

static void ipmmu_iotlb_sync(struct iommu_domain *io_domain,
			     struct iommu_iotlb_gather *gather)
{
	ipmmu_flush_iotlb_all(io_domain);
}

static phys_addr_t ipmmu_iova_to_phys(struct iommu_domain *io_domain,
				      dma_addr_t iova)
{
	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);

	/* TODO: Is locking needed ? */

	return domain->iop->iova_to_phys(domain->iop, iova);
}

static int ipmmu_init_platform_device(struct device *dev,
				      const struct of_phandle_args *args)
{
	struct platform_device *ipmmu_pdev;

	ipmmu_pdev = of_find_device_by_node(args->np);
	if (!ipmmu_pdev)
		return -ENODEV;

	dev_iommu_priv_set(dev, platform_get_drvdata(ipmmu_pdev));

	return 0;
}

static const struct soc_device_attribute soc_needs_opt_in[] = {
	{ .family = "R-Car Gen3", },
	{ .family = "R-Car Gen4", },
	{ .family = "RZ/G2", },
	{ /* sentinel */ }
};

static const struct soc_device_attribute soc_denylist[] = {
	{ .soc_id = "r8a774a1", },
	{ .soc_id = "r8a7795", .revision = "ES2.*" },
	{ .soc_id = "r8a7796", },
	{ /* sentinel */ }
};

static const char * const devices_allowlist[] = {
	"ee100000.mmc",
	"ee120000.mmc",
	"ee140000.mmc",
	"ee160000.mmc"
};

static bool ipmmu_device_is_allowed(struct device *dev)
{
	unsigned int i;

	/*
	 * R-Car Gen3/4 and RZ/G2 use the allow list to opt-in devices.
	 * For Other SoCs, this returns true anyway.
	 */
	if (!soc_device_match(soc_needs_opt_in))
		return true;

	/* Check whether this SoC can use the IPMMU correctly or not */
	if (soc_device_match(soc_denylist))
		return false;

	/* Check whether this device is a PCI device */
	if (dev_is_pci(dev))
		return true;

	/* Check whether this device can work with the IPMMU */
	for (i = 0; i < ARRAY_SIZE(devices_allowlist); i++) {
		if (!strcmp(dev_name(dev), devices_allowlist[i]))
			return true;
	}

	/* Otherwise, do not allow use of IPMMU */
	return false;
}

static int ipmmu_of_xlate(struct device *dev,
			  const struct of_phandle_args *spec)
{
	if (!ipmmu_device_is_allowed(dev))
		return -ENODEV;

	iommu_fwspec_add_ids(dev, spec->args, 1);

	/* Initialize once - xlate() will call multiple times */
	if (to_ipmmu(dev))
		return 0;

	return ipmmu_init_platform_device(dev, spec);
}

static int ipmmu_init_arm_mapping(struct device *dev)
{
	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);
	int ret;

	/*
	 * Create the ARM mapping, used by the ARM DMA mapping core to allocate
	 * VAs. This will allocate a corresponding IOMMU domain.
	 *
	 * TODO:
	 * - Create one mapping per context (TLB).
	 * - Make the mapping size configurable ? We currently use a 2GB mapping
	 *   at a 1GB offset to ensure that NULL VAs will fault.
	 */
	if (!mmu->mapping) {
		struct dma_iommu_mapping *mapping;

		mapping = arm_iommu_create_mapping(dev, SZ_1G, SZ_2G);
		if (IS_ERR(mapping)) {
			dev_err(mmu->dev, "failed to create ARM IOMMU mapping\n");
			ret = PTR_ERR(mapping);
			goto error;
		}

		mmu->mapping = mapping;
	}

	/* Attach the ARM VA mapping to the device. */
	ret = arm_iommu_attach_device(dev, mmu->mapping);
	if (ret < 0) {
		dev_err(dev, "Failed to attach device to VA mapping\n");
		goto error;
	}

	return 0;

error:
	if (mmu->mapping)
		arm_iommu_release_mapping(mmu->mapping);

	return ret;
}

static struct iommu_device *ipmmu_probe_device(struct device *dev)
{
	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);

	/*
	 * Only let through devices that have been verified in xlate()
	 */
	if (!mmu)
		return ERR_PTR(-ENODEV);

	return &mmu->iommu;
}

static void ipmmu_probe_finalize(struct device *dev)
{
	int ret = 0;

	if (IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_IOMMU_DMA))
		ret = ipmmu_init_arm_mapping(dev);

	if (ret)
		dev_err(dev, "Can't create IOMMU mapping - DMA-OPS will not work\n");
}

static void ipmmu_release_device(struct device *dev)
{
	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);
	unsigned int i;

	for (i = 0; i < fwspec->num_ids; ++i) {
		unsigned int utlb = fwspec->ids[i];

		ipmmu_imuctr_write(mmu, utlb, 0);
		mmu->utlb_ctx[utlb] = IPMMU_CTX_INVALID;
	}

	arm_iommu_release_mapping(mmu->mapping);
}

static const struct iommu_ops ipmmu_ops = {
	.identity_domain = &ipmmu_iommu_identity_domain,
	.domain_alloc_paging = ipmmu_domain_alloc_paging,
	.probe_device = ipmmu_probe_device,
	.release_device = ipmmu_release_device,
	.probe_finalize = ipmmu_probe_finalize,
	/*
	 * FIXME: The device grouping is a fixed property of the hardware's
	 * ability to isolate and control DMA, it should not depend on kconfig.
	 */
	.device_group = IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_IOMMU_DMA)
			? generic_device_group : generic_single_device_group,
	.pgsize_bitmap = SZ_1G | SZ_2M | SZ_4K,
	.of_xlate = ipmmu_of_xlate,
	.default_domain_ops = &(const struct iommu_domain_ops) {
		.attach_dev	= ipmmu_attach_device,
		.map_pages	= ipmmu_map,
		.unmap_pages	= ipmmu_unmap,
		.flush_iotlb_all = ipmmu_flush_iotlb_all,
		.iotlb_sync	= ipmmu_iotlb_sync,
		.iova_to_phys	= ipmmu_iova_to_phys,
		.free		= ipmmu_domain_free,
	}
};

/* -----------------------------------------------------------------------------
 * Probe/remove and init
 */

static void ipmmu_device_reset(struct ipmmu_vmsa_device *mmu)
{
	unsigned int i;

	/* Disable all contexts. */
	for (i = 0; i < mmu->num_ctx; ++i)
		ipmmu_ctx_write(mmu, i, IMCTR, 0);
}

static const struct ipmmu_features ipmmu_features_default = {
	.use_ns_alias_offset = true,
	.has_cache_leaf_nodes = false,
	.number_of_contexts = 1, /* software only tested with one context */
	.num_utlbs = 32,
	.setup_imbuscr = true,
	.twobit_imttbcr_sl0 = false,
	.reserved_context = false,
	.cache_snoop = true,
	.ctx_offset_base = 0,
	.ctx_offset_stride = 0x40,
	.utlb_offset_base = 0,
};

static const struct ipmmu_features ipmmu_features_rcar_gen3 = {
	.use_ns_alias_offset = false,
	.has_cache_leaf_nodes = true,
	.number_of_contexts = 8,
	.num_utlbs = 48,
	.setup_imbuscr = false,
	.twobit_imttbcr_sl0 = true,
	.reserved_context = true,
	.cache_snoop = false,
	.ctx_offset_base = 0,
	.ctx_offset_stride = 0x40,
	.utlb_offset_base = 0,
};

static const struct ipmmu_features ipmmu_features_rcar_gen4 = {
	.use_ns_alias_offset = false,
	.has_cache_leaf_nodes = true,
	.number_of_contexts = 16,
	.num_utlbs = 64,
	.setup_imbuscr = false,
	.twobit_imttbcr_sl0 = true,
	.reserved_context = true,
	.cache_snoop = false,
	.ctx_offset_base = 0x10000,
	.ctx_offset_stride = 0x1040,
	.utlb_offset_base = 0x3000,
};

static const struct of_device_id ipmmu_of_ids[] = {
	{
		.compatible = "renesas,ipmmu-vmsa",
		.data = &ipmmu_features_default,
	}, {
		.compatible = "renesas,ipmmu-r8a774a1",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a774b1",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a774c0",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a774e1",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a7795",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a7796",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a77961",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a77965",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a77970",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a77980",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a77990",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a77995",
		.data = &ipmmu_features_rcar_gen3,
	}, {
		.compatible = "renesas,ipmmu-r8a779a0",
		.data = &ipmmu_features_rcar_gen4,
	}, {
		.compatible = "renesas,rcar-gen4-ipmmu-vmsa",
		.data = &ipmmu_features_rcar_gen4,
	}, {
		/* Terminator */
	},
};

static int ipmmu_probe(struct platform_device *pdev)
{
	struct ipmmu_vmsa_device *mmu;
	int irq;
	int ret;

	mmu = devm_kzalloc(&pdev->dev, sizeof(*mmu), GFP_KERNEL);
	if (!mmu) {
		dev_err(&pdev->dev, "cannot allocate device data\n");
		return -ENOMEM;
	}

	mmu->dev = &pdev->dev;
	spin_lock_init(&mmu->lock);
	bitmap_zero(mmu->ctx, IPMMU_CTX_MAX);
	mmu->features = of_device_get_match_data(&pdev->dev);
	memset(mmu->utlb_ctx, IPMMU_CTX_INVALID, mmu->features->num_utlbs);
	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
	if (ret)
		return ret;

	/* Map I/O memory and request IRQ. */
	mmu->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(mmu->base))
		return PTR_ERR(mmu->base);

	/*
	 * The IPMMU has two register banks, for secure and non-secure modes.
	 * The bank mapped at the beginning of the IPMMU address space
	 * corresponds to the running mode of the CPU. When running in secure
	 * mode the non-secure register bank is also available at an offset.
	 *
	 * Secure mode operation isn't clearly documented and is thus currently
	 * not implemented in the driver. Furthermore, preliminary tests of
	 * non-secure operation with the main register bank were not successful.
	 * Offset the registers base unconditionally to point to the non-secure
	 * alias space for now.
	 */
	if (mmu->features->use_ns_alias_offset)
		mmu->base += IM_NS_ALIAS_OFFSET;

	mmu->num_ctx = min(IPMMU_CTX_MAX, mmu->features->number_of_contexts);

	/*
	 * Determine if this IPMMU instance is a root device by checking for
	 * the lack of has_cache_leaf_nodes flag or renesas,ipmmu-main property.
	 */
	if (!mmu->features->has_cache_leaf_nodes ||
	    !of_property_present(pdev->dev.of_node, "renesas,ipmmu-main"))
		mmu->root = mmu;
	else
		mmu->root = ipmmu_find_root();

	/*
	 * Wait until the root device has been registered for sure.
	 */
	if (!mmu->root)
		return -EPROBE_DEFER;

	/* Root devices have mandatory IRQs */
	if (ipmmu_is_root(mmu)) {
		irq = platform_get_irq(pdev, 0);
		if (irq < 0)
			return irq;

		ret = devm_request_irq(&pdev->dev, irq, ipmmu_irq, 0,
				       dev_name(&pdev->dev), mmu);
		if (ret < 0) {
			dev_err(&pdev->dev, "failed to request IRQ %d\n", irq);
			return ret;
		}

		ipmmu_device_reset(mmu);

		if (mmu->features->reserved_context) {
			dev_info(&pdev->dev, "IPMMU context 0 is reserved\n");
			set_bit(0, mmu->ctx);
		}
	}

	/*
	 * Register the IPMMU to the IOMMU subsystem in the following cases:
	 * - R-Car Gen2 IPMMU (all devices registered)
	 * - R-Car Gen3 IPMMU (leaf devices only - skip root IPMMU-MM device)
	 */
	if (!mmu->features->has_cache_leaf_nodes || !ipmmu_is_root(mmu)) {
		ret = iommu_device_sysfs_add(&mmu->iommu, &pdev->dev, NULL,
					     dev_name(&pdev->dev));
		if (ret)
			return ret;

		ret = iommu_device_register(&mmu->iommu, &ipmmu_ops, &pdev->dev);
		if (ret)
			return ret;
	}

	/*
	 * We can't create the ARM mapping here as it requires the bus to have
	 * an IOMMU, which only happens when bus_set_iommu() is called in
	 * ipmmu_init() after the probe function returns.
	 */

	platform_set_drvdata(pdev, mmu);

	return 0;
}

static void ipmmu_remove(struct platform_device *pdev)
{
	struct ipmmu_vmsa_device *mmu = platform_get_drvdata(pdev);

	iommu_device_sysfs_remove(&mmu->iommu);
	iommu_device_unregister(&mmu->iommu);

	arm_iommu_release_mapping(mmu->mapping);

	ipmmu_device_reset(mmu);
}

static int ipmmu_resume_noirq(struct device *dev)
{
	struct ipmmu_vmsa_device *mmu = dev_get_drvdata(dev);
	unsigned int i;

	/* Reset root MMU and restore contexts */
	if (ipmmu_is_root(mmu)) {
		ipmmu_device_reset(mmu);

		for (i = 0; i < mmu->num_ctx; i++) {
			if (!mmu->domains[i])
				continue;

			ipmmu_domain_setup_context(mmu->domains[i]);
		}
	}

	/* Re-enable active micro-TLBs */
	for (i = 0; i < mmu->features->num_utlbs; i++) {
		if (mmu->utlb_ctx[i] == IPMMU_CTX_INVALID)
			continue;

		ipmmu_utlb_enable(mmu->root->domains[mmu->utlb_ctx[i]], i);
	}

	return 0;
}

static const struct dev_pm_ops ipmmu_pm  = {
	NOIRQ_SYSTEM_SLEEP_PM_OPS(NULL, ipmmu_resume_noirq)
};

static struct platform_driver ipmmu_driver = {
	.driver = {
		.name = "ipmmu-vmsa",
		.of_match_table = ipmmu_of_ids,
		.pm = pm_sleep_ptr(&ipmmu_pm),
	},
	.probe = ipmmu_probe,
	.remove_new = ipmmu_remove,
};
builtin_platform_driver(ipmmu_driver);